Pub Date : 2026-01-27DOI: 10.1016/j.gete.2026.100794
German David Matos-Paucar , Merita Tafili , Jan Machaček , Torsten Wichtmann
The soil–water retention curve (SWRC) is fundamental in geotechnical engineering, influencing the hydraulic and mechanical response of unsaturated soils. This study evaluates three generalised SWRC models that account for density effects and/or hydraulic hysteresis: the Gallipoli, Sun, and Gao formulations. Their simulation performance is assessed against experimental data from a wide range of soils, including compacted till, Pearl clays, Barcelona silt, and silty sands. The analyses highlight the strengths and limitations of each model in reproducing main wetting and drying branches, scanning curves, and density-dependent shifts of the SWRC. Among the tested formulations, the Gao model demonstrates the most robust capability to represent hysteresis and density effects across broad suction ranges. Finally, selected hydraulic models were coupled with the hypoplastic constitutive model proposed by Tafili and Machaček (2023) to evaluate hydro–mechanical interactions of unsaturated soils under various stress and hydraulic conditions, highlighting that the choice of SWRC formulation strongly influences predictions of volumetric response, stiffness evolution, and suction-dependent strength. This underlines the importance of selecting an appropriate SWRC model for reliable hydro–mechanical modelling of unsaturated soils.
{"title":"Evaluation of generalised soil water retention models and their role in hydro–mechanical modelling of unsaturated soils","authors":"German David Matos-Paucar , Merita Tafili , Jan Machaček , Torsten Wichtmann","doi":"10.1016/j.gete.2026.100794","DOIUrl":"10.1016/j.gete.2026.100794","url":null,"abstract":"<div><div>The soil–water retention curve (SWRC) is fundamental in geotechnical engineering, influencing the hydraulic and mechanical response of unsaturated soils. This study evaluates three generalised SWRC models that account for density effects and/or hydraulic hysteresis: the Gallipoli, Sun, and Gao formulations. Their simulation performance is assessed against experimental data from a wide range of soils, including compacted till, Pearl clays, Barcelona silt, and silty sands. The analyses highlight the strengths and limitations of each model in reproducing main wetting and drying branches, scanning curves, and density-dependent shifts of the SWRC. Among the tested formulations, the Gao model demonstrates the most robust capability to represent hysteresis and density effects across broad suction ranges. Finally, selected hydraulic models were coupled with the hypoplastic constitutive model proposed by Tafili and Machaček (2023) to evaluate hydro–mechanical interactions of unsaturated soils under various stress and hydraulic conditions, highlighting that the choice of SWRC formulation strongly influences predictions of volumetric response, stiffness evolution, and suction-dependent strength. This underlines the importance of selecting an appropriate SWRC model for reliable hydro–mechanical modelling of unsaturated soils.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100794"},"PeriodicalIF":3.7,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-25DOI: 10.1016/j.gete.2026.100795
Felipe Firmino Diniz , Jordan Carneiro Martins de Souza , Pabllo da Silva Araujo , Tuilly de Fátima Furtado Guerra , Rejane Nascentes , Luiz Moreira Coelho Junior , Veruschka Escarião Dessoles Monteiro , Márcio Camargo de Melo
The efficiency of landfill cover layers in gas retention is vital to mitigate environmental impacts, reduce biogas modeling uncertainties, and promote resource circularity and low-carbon transitions. This study applies the Geotechnical Performance Index (GPI) to evaluate the spatial relationship between geotechnical properties and greenhouse gas (GHG) emissions in a landfill in northeastern Brazil. The data was obtained through laboratory testing of the soil from the site, in situ testing at 21 points in the cover layer and physical-mechanical characterization of the soil. The GPI included parameters such as moisture (w), degree of compaction (C), dry density (γd), void ratio (e), porosity (n) and degree of saturation (S). Interpolate the data using QGIS®, I'Moran to analyze the spatial correlation and Global Warming Potential (GWP) analyzes. The CH4 concentrations, of the 21 points analyzed, 95 % registered average values of less than 4 % v/v. The main CO2 hotspot had a flow of > 300 g.m−2.d−1, while for CH4 it was 39 g.m−2.d−1. The GPI was suitable for assessing the efficiency of the landfill cover layer, showing positive spatial correlations with CO2 (Moran's I = 0.105) and CH4 (Moran's I = 0.064) fluxes. Under conservative, moderate and optimistic carbon-pricing scenarios (CO2-eq), annual revenue estimates amounted to USD 63,285, USD 189,855 and USD 632,850, respectively, which highlights the economic leverage of methane-oriented interventions. The contributions demonstrate that landfill cover performance arises from coupled geotechnical, environmental, and biogeochemical interactions; targeted interventions can therefore elicit integrated responses and strengthen decision-making for landfill management and climate change mitigation.
垃圾填埋场覆盖层的气体保留效率对于减轻环境影响、减少沼气模型的不确定性、促进资源循环和低碳转型至关重要。本研究应用岩土性能指数（GPI）对巴西东北部某垃圾填埋场岩土性能与温室气体（GHG）排放的空间关系进行了评价。这些数据是通过对现场土壤的实验室测试、覆盖层21个点的现场测试和土壤的物理力学表征获得的。GPI包括含水率(w)、压实度(C)、干密度（γd）、孔隙率(e)、孔隙率(n)和饱和度(S)等参数。使用QGIS®、I’moran对数据进行插值，分析空间相关性和全球变暖潜势（GWP）分析。分析的21个点中，95 %的CH4浓度平均值小于4 % v/v。主要的CO2热点流量为>； 300 g.m−2。而CH4为39 g.m−2.d−1。GPI与CO2 （Moran’s I = 0.105）和CH4 （Moran’s I = 0.064）通量呈空间正相关，适于评价填埋场覆盖层的效率。在保守、适度和乐观的碳定价情景（二氧化碳当量）下，年收入估计分别为63,285美元、189,855美元和632,850美元，这凸显了以甲烷为导向的干预措施的经济杠杆作用。研究表明，垃圾填埋场覆盖性能是由岩土、环境和生物地球化学相互作用引起的；因此，有针对性的干预措施可以引发综合反应，并加强垃圾填埋场管理和减缓气候变化的决策。
{"title":"Geotechnical performance index to validate landfill cover efficiency: Cleaner production and circular economy in the Brazilian semi-arid region","authors":"Felipe Firmino Diniz , Jordan Carneiro Martins de Souza , Pabllo da Silva Araujo , Tuilly de Fátima Furtado Guerra , Rejane Nascentes , Luiz Moreira Coelho Junior , Veruschka Escarião Dessoles Monteiro , Márcio Camargo de Melo","doi":"10.1016/j.gete.2026.100795","DOIUrl":"10.1016/j.gete.2026.100795","url":null,"abstract":"<div><div>The efficiency of landfill cover layers in gas retention is vital to mitigate environmental impacts, reduce biogas modeling uncertainties, and promote resource circularity and low-carbon transitions. This study applies the Geotechnical Performance Index (GPI) to evaluate the spatial relationship between geotechnical properties and greenhouse gas (GHG) emissions in a landfill in northeastern Brazil. The data was obtained through laboratory testing of the soil from the site, in situ testing at 21 points in the cover layer and physical-mechanical characterization of the soil. The GPI included parameters such as moisture (w), degree of compaction (C), dry density (γ<sub>d</sub>), void ratio (<em>e</em>), porosity (<em>n</em>) and degree of saturation (S). Interpolate the data using QGIS®, I'Moran to analyze the spatial correlation and Global Warming Potential (GWP) analyzes. The CH<sub>4</sub> concentrations, of the 21 points analyzed, 95 % registered average values of less than 4 % v/v. The main CO<sub>2</sub> hotspot had a flow of > 300 g.m<sup>−2</sup>.d<sup>−1</sup>, while for CH<sub>4</sub> it was 39 g.m<sup>−2</sup>.d<sup>−1</sup>. The GPI was suitable for assessing the efficiency of the landfill cover layer, showing positive spatial correlations with CO<sub>2</sub> (Moran's I = 0.105) and CH<sub>4</sub> (Moran's I = 0.064) fluxes. Under conservative, moderate and optimistic carbon-pricing scenarios (CO<sub>2-eq</sub>), annual revenue estimates amounted to USD 63,285, USD 189,855 and USD 632,850, respectively, which highlights the economic leverage of methane-oriented interventions. The contributions demonstrate that landfill cover performance arises from coupled geotechnical, environmental, and biogeochemical interactions; targeted interventions can therefore elicit integrated responses and strengthen decision-making for landfill management and climate change mitigation.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100795"},"PeriodicalIF":3.7,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.gete.2026.100791
Marcelo Menezes Farias , Ivens da Costa Menezes Lima , Francisco Marcondes , Kamy Sepehrnoori
This work presents an unstructured grid-based formulation for compositional reservoir simulation coupled with elastic, elastoplastic, and viscoplastic geomechanical models. Implemented in the UTCOMPRS simulator using the Element-based Finite Volume Method (EbFVM), the proposed approach explicitly solves both flow and mechanical equations on unstructured grids. It supports nonlinear models, such as Mohr-Coulomb, Drucker-Prager, and a Perzyna-based viscoplastic criterion to represent material yield. Five case studies are conducted to verify the geomechanical implementation: Prandtl’s benchmark validates the plastic and viscoplastic models; primary production matched results from a commercial simulator; WAG injection and CO2 storage cases demonstrated the influence of the geomechanical model on production forecast, reservoir pressure, and rock deformation; and a Pre-Salt reservoir proxy tested computational efficiency, and numerical accuracy of the EbFVM across multiple grid refinements. Results show that the EbFVM captures nonlinear deformation while delivering solutions comparable to fine meshes using significantly coarser grids. The proposed formulation provides a robust and versatile tool for simulating complex reservoir-geomechanical problems.
{"title":"A unified Element-based Finite Volume Method for linear and nonlinear geomechanics and compositional reservoir simulation","authors":"Marcelo Menezes Farias , Ivens da Costa Menezes Lima , Francisco Marcondes , Kamy Sepehrnoori","doi":"10.1016/j.gete.2026.100791","DOIUrl":"10.1016/j.gete.2026.100791","url":null,"abstract":"<div><div>This work presents an unstructured grid-based formulation for compositional reservoir simulation coupled with elastic, elastoplastic, and viscoplastic geomechanical models. Implemented in the UTCOMPRS simulator using the Element-based Finite Volume Method (EbFVM), the proposed approach explicitly solves both flow and mechanical equations on unstructured grids. It supports nonlinear models, such as Mohr-Coulomb, Drucker-Prager, and a Perzyna-based viscoplastic criterion to represent material yield. Five case studies are conducted to verify the geomechanical implementation: Prandtl’s benchmark validates the plastic and viscoplastic models; primary production matched results from a commercial simulator; WAG injection and CO<sub>2</sub> storage cases demonstrated the influence of the geomechanical model on production forecast, reservoir pressure, and rock deformation; and a Pre-Salt reservoir proxy tested computational efficiency, and numerical accuracy of the EbFVM across multiple grid refinements. Results show that the EbFVM captures nonlinear deformation while delivering solutions comparable to fine meshes using significantly coarser grids. The proposed formulation provides a robust and versatile tool for simulating complex reservoir-geomechanical problems.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100791"},"PeriodicalIF":3.7,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.gete.2026.100793
Yang Shen , Baiquan Lin , Minghua Lin , Ting Liu , Tong Liu , Zhiyong Hao , Wei Yang
The fracture zone of abandoned mining sites is prone to Mode-I fractures. In coal rock layers with more aquifers, the erosion and dissolution of abandoned mine water will accelerate this process. To investigate the respective effects and contributions of swelling and erosion on Mode-I fracture in abandoned mine water, this study combines laboratory experiments and discrete element simulations to explore the macro- and micro-fracture processes of samples under the coupled action of erosion and swelling. Five time gradients were set for treating the prepared NSCB samples (0, 7, 14, 21, 30 days), and the degree of deterioration of the Mode-I fracture toughness of the coal samples was explored. A mechanical model for mineral dissolution-swelling was established by combining Computed Tomography(CT) scanning and the discrete element grain-based model (GBM). The Swelling/ dissolution expansion coefficient were defined, by adjusting the expansion coefficient, the model simulates the damage process of coal particles and minerals undergoing dissolution-swelling. The research results indicate that the failure behavior transitions from brittle fracture to ductile fracture. Simulation results indicate that the initial stage of contact between abandoned mine water and coal is primarily characterized by hydraulic swelling, with corrosion starting to affect the sample in the later stages of contact. It is observed that corrosion leads to an increase in transgranular cracks during Mode-I fracture processes, whereas the original sample primarily experiences slip fracture along mineral crystal boundaries.
{"title":"The contribution of physical-chemical effects of abandoned mine water to the deterioration of Mode-I fracture toughness- based on CT-DEM integrated modeling","authors":"Yang Shen , Baiquan Lin , Minghua Lin , Ting Liu , Tong Liu , Zhiyong Hao , Wei Yang","doi":"10.1016/j.gete.2026.100793","DOIUrl":"10.1016/j.gete.2026.100793","url":null,"abstract":"<div><div>The fracture zone of abandoned mining sites is prone to Mode-I fractures. In coal rock layers with more aquifers, the erosion and dissolution of abandoned mine water will accelerate this process. To investigate the respective effects and contributions of swelling and erosion on Mode-I fracture in abandoned mine water, this study combines laboratory experiments and discrete element simulations to explore the macro- and micro-fracture processes of samples under the coupled action of erosion and swelling. Five time gradients were set for treating the prepared NSCB samples (0, 7, 14, 21, 30 days), and the degree of deterioration of the Mode-I fracture toughness of the coal samples was explored. A mechanical model for mineral dissolution-swelling was established by combining Computed Tomography(CT) scanning and the discrete element grain-based model (GBM). The Swelling/ dissolution expansion coefficient were defined, by adjusting the expansion coefficient, the model simulates the damage process of coal particles and minerals undergoing dissolution-swelling. The research results indicate that the failure behavior transitions from brittle fracture to ductile fracture. Simulation results indicate that the initial stage of contact between abandoned mine water and coal is primarily characterized by hydraulic swelling, with corrosion starting to affect the sample in the later stages of contact. It is observed that corrosion leads to an increase in transgranular cracks during Mode-I fracture processes, whereas the original sample primarily experiences slip fracture along mineral crystal boundaries.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100793"},"PeriodicalIF":3.7,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.gete.2026.100792
Zhongzhong Xu , Jiulong Cheng , Hongpeng Zhao
The key to preventing mine water disasters and gas hazards lies in monitoring the development of mining–induced fractures in the roof strata of coal seams. Although the borehole resistivity method (BRM) is an advanced technology, its effectiveness is limited by the incomplete understanding of how the apparent resistivity of rock varies during the development of mining-induced fractures and the difficulty in quantitatively analyzing the extent of fracture development. This study used experimental analysis to identify the patterns governing the apparent resistivity changes of rock throughout the development of mining-induced fractures under different confining pressure levels and to formulate a quantitative model for assessing rock fracture development. The study examined stress and the apparent resistivity of five rock types under three confining pressure levels. The results reveal that the relationship between stress and apparent resistivity in loaded rocks is characterized by distinct stage–dependent variations. Specifically, during the microcrack closure stage, there is a negative linear correlation between the apparent resistivity of the rock and stress. In the linear elastic stage, the apparent resistivity of identical rocks remains stable and consistent across varying confining pressure levels. Conversely, in the stable crack propagation and failure stages, a positive linear correlation is observed between the apparent resistivity of the rock and stress. Utilizing experimental data, a coupled stress–apparent resistivity model for rock deformation and failure (CSAR model) was developed. This study not only improves the precision of BRM in monitoring mining-induced fracture development in coal seam roof strata but also tackles the challenges of quantitatively analyzing the extent of fracture development.
{"title":"Coupled stress–apparent resistivity model for rock deformation and failure based on experimental analysis","authors":"Zhongzhong Xu , Jiulong Cheng , Hongpeng Zhao","doi":"10.1016/j.gete.2026.100792","DOIUrl":"10.1016/j.gete.2026.100792","url":null,"abstract":"<div><div>The key to preventing mine water disasters and gas hazards lies in monitoring the development of mining–induced fractures in the roof strata of coal seams. Although the borehole resistivity method (BRM) is an advanced technology, its effectiveness is limited by the incomplete understanding of how the apparent resistivity of rock varies during the development of mining-induced fractures and the difficulty in quantitatively analyzing the extent of fracture development. This study used experimental analysis to identify the patterns governing the apparent resistivity changes of rock throughout the development of mining-induced fractures under different confining pressure levels and to formulate a quantitative model for assessing rock fracture development. The study examined stress and the apparent resistivity of five rock types under three confining pressure levels. The results reveal that the relationship between stress and apparent resistivity in loaded rocks is characterized by distinct stage–dependent variations. Specifically, during the microcrack closure stage, there is a negative linear correlation between the apparent resistivity of the rock and stress. In the linear elastic stage, the apparent resistivity of identical rocks remains stable and consistent across varying confining pressure levels. Conversely, in the stable crack propagation and failure stages, a positive linear correlation is observed between the apparent resistivity of the rock and stress. Utilizing experimental data, a coupled stress–apparent resistivity model for rock deformation and failure (CSAR model) was developed. This study not only improves the precision of BRM in monitoring mining-induced fracture development in coal seam roof strata but also tackles the challenges of quantitatively analyzing the extent of fracture development.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100792"},"PeriodicalIF":3.7,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-09DOI: 10.1016/j.gete.2026.100790
Chengyun Ma , Zehan Zheng , Yihua Dou , Wenjun Shan , Wei Wang
Lost circulation in fractured formations is a critical issue, and accurate estimation of fracture width is essential for effective plugging. However, existing analytical models (e.g., Sanfilippo and Civan models) typically involve complex implicit solutions, neglect fracture deformation, and require numerous rock mechanics parameters that are difficult to obtain in real-time. To overcome these limitations, this study developed a 3D multi-scale loss model based on fluid-solid coupling to simulate the loss process dynamically. Based on the simulation results, a rapid fracture width inversion strategy was proposed. A distinct advantage of this approach is its flexibility regarding data availability: inversion models were established for two scenarios—one incorporating fracture density and another excluding it. Specifically, for wells lacking fracture density data (e.g., no imaging logs), the simplified model excluding fracture density allows for accurate prediction using only three readily available parameters: fluid viscosity, pressure differential, and cumulative loss volume. Validated against 48 sets of field data, this simplified model achieved a coefficient of determination (R2) of 0.888 with a relative error of less than 10 %. Compared to traditional methods, the proposed approach significantly reduces parameter requirements and computational complexity, providing a practical and efficient tool for on-site decision-making.
{"title":"Research on drilling fluid lost circulation and fracture width inversion in complex fractured formations based on fluid-solid coupling","authors":"Chengyun Ma , Zehan Zheng , Yihua Dou , Wenjun Shan , Wei Wang","doi":"10.1016/j.gete.2026.100790","DOIUrl":"10.1016/j.gete.2026.100790","url":null,"abstract":"<div><div>Lost circulation in fractured formations is a critical issue, and accurate estimation of fracture width is essential for effective plugging. However, existing analytical models (e.g., Sanfilippo and Civan models) typically involve complex implicit solutions, neglect fracture deformation, and require numerous rock mechanics parameters that are difficult to obtain in real-time. To overcome these limitations, this study developed a 3D multi-scale loss model based on fluid-solid coupling to simulate the loss process dynamically. Based on the simulation results, a rapid fracture width inversion strategy was proposed. A distinct advantage of this approach is its flexibility regarding data availability: inversion models were established for two scenarios—one incorporating fracture density and another excluding it. Specifically, for wells lacking fracture density data (e.g., no imaging logs), the simplified model excluding fracture density allows for accurate prediction using only three readily available parameters: fluid viscosity, pressure differential, and cumulative loss volume. Validated against 48 sets of field data, this simplified model achieved a coefficient of determination (R<sup>2</sup>) of 0.888 with a relative error of less than 10 %. Compared to traditional methods, the proposed approach significantly reduces parameter requirements and computational complexity, providing a practical and efficient tool for on-site decision-making.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100790"},"PeriodicalIF":3.7,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The low penetration rate is one of the limitations of ultra-deep well drilling, which usually results from the high strength of formation rock with high in-situ stress. The shock-assisted-drilling technique has been proven to be effective in improving the penetration rate of deep rock; however, the fragmentation mechanism is still not clear. Benefiting from the advantages of Peridynamics in simulating crack-involved problems, this paper first introduces the concepts of ordinary state-based Peridynamics and the nonlocal plastic deformation. Then, the nonlocal strain rate effect is reconstructed by reformulating the Peridynamic constitutive relations with the Johnson-Cook model, and the numerical algorithm is developed subsequently. The strain rate effect of yield strength is then validated by solving a benchmark example of uniaxial loading; the stress-strain relation subjected to different load rates is generated. To further investigate the fragmentation under different load rates, the crack propagation of the Brazilian Disk subjected to the Split Hopkinson test is simulated. The crack propagation simulation of BD with/without a slot is consistent with the experiment results. Furthermore, the research systematically reveals the coupling influence of cutter impact and in-situ stress on rock damage evolution and plastic deformation. The numerical simulation demonstrates the stress regulation and damage suppression effects of cutter impact under different in-situ stresses. The dynamic behavior of the rock exhibits a strain-rate-strengthening characteristic and shows a positive correlation between yield strength and strain rate. These findings elucidated the damage evolution mechanism of deep formation rock under impact loads.
{"title":"Peridynamic simulation of deep rock fragmentation subjected to cutter impact with Johnson-Cook model","authors":"Jingkai Chen, Dong Jiang, Zhangcong Huang, Xiaomin Zhang","doi":"10.1016/j.gete.2026.100789","DOIUrl":"10.1016/j.gete.2026.100789","url":null,"abstract":"<div><div>The low penetration rate is one of the limitations of ultra-deep well drilling, which usually results from the high strength of formation rock with high in-situ stress. The shock-assisted-drilling technique has been proven to be effective in improving the penetration rate of deep rock; however, the fragmentation mechanism is still not clear. Benefiting from the advantages of Peridynamics in simulating crack-involved problems, this paper first introduces the concepts of ordinary state-based Peridynamics and the nonlocal plastic deformation. Then, the nonlocal strain rate effect is reconstructed by reformulating the Peridynamic constitutive relations with the Johnson-Cook model, and the numerical algorithm is developed subsequently. The strain rate effect of yield strength is then validated by solving a benchmark example of uniaxial loading; the stress-strain relation subjected to different load rates is generated. To further investigate the fragmentation under different load rates, the crack propagation of the Brazilian Disk subjected to the Split Hopkinson test is simulated. The crack propagation simulation of BD with/without a slot is consistent with the experiment results. Furthermore, the research systematically reveals the coupling influence of cutter impact and in-situ stress on rock damage evolution and plastic deformation. The numerical simulation demonstrates the stress regulation and damage suppression effects of cutter impact under different in-situ stresses. The dynamic behavior of the rock exhibits a strain-rate-strengthening characteristic and shows a positive correlation between yield strength and strain rate. These findings elucidated the damage evolution mechanism of deep formation rock under impact loads.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100789"},"PeriodicalIF":3.7,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-05DOI: 10.1016/j.gete.2026.100788
Changde Yang , Yang Chen , Binbin Yang
This study introduces the results of evaporation cracking test on soil with different discrete polypropylene fiber content (PPFC). Changes in the cracking characteristics are quantitatively analyzed by using digital image processing technology. The results indicate that the fractal dimension (FD) of the cracking process can be divided into three stages. Stage A is defined as the rapid cracking stage when the rate of cracking increases rapidly with a PPFC of 0.2 %. However, the rate of cracking decreases with further increases in PPFC. In Stage B, the FD of cracks with a PPFC of 0.2 % and 0.7 % tends to be stable at first, while that of cracks with a PPFC less than 0.2 % increases gradually with time. The FD approaches a constant in Stage C and its value decreases with increases in the PPFC. The characteristics of the average moisture content of soil with different PPFC along with the drying time show a close agreement with those when the PPFC is less than 0.2 %. It is found that fibers can restrain the expansion of soil which reduces cracking and evaporation of free water which results in a delay of the evaporation of the bounded water. The 0.2 % PPFC is the optimal ratio for inhibiting Xinjiang clay.
{"title":"Desiccation cracking behavior of discrete fiber mixed with clay material","authors":"Changde Yang , Yang Chen , Binbin Yang","doi":"10.1016/j.gete.2026.100788","DOIUrl":"10.1016/j.gete.2026.100788","url":null,"abstract":"<div><div>This study introduces the results of evaporation cracking test on soil with different discrete polypropylene fiber content (PPFC). Changes in the cracking characteristics are quantitatively analyzed by using digital image processing technology. The results indicate that the fractal dimension (FD) of the cracking process can be divided into three stages. Stage A is defined as the rapid cracking stage when the rate of cracking increases rapidly with a PPFC of 0.2 %. However, the rate of cracking decreases with further increases in PPFC. In Stage B, the FD of cracks with a PPFC of 0.2 % and 0.7 % tends to be stable at first, while that of cracks with a PPFC less than 0.2 % increases gradually with time. The FD approaches a constant in Stage C and its value decreases with increases in the PPFC. The characteristics of the average moisture content of soil with different PPFC along with the drying time show a close agreement with those when the PPFC is less than 0.2 %. It is found that fibers can restrain the expansion of soil which reduces cracking and evaporation of free water which results in a delay of the evaporation of the bounded water. The 0.2 % PPFC is the optimal ratio for inhibiting Xinjiang clay.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100788"},"PeriodicalIF":3.7,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-05DOI: 10.1016/j.gete.2026.100787
Sandro Andrés , David Santillán , Ruben Juanes , Luis Cueto-Felgueroso
Supershear earthquakes are a particular class of seismic events in which the rupture velocity exceeds the shear wave velocity. These high-speed ruptures challenge conventional fault mechanics and have significant implications for the assessment of seismic hazards. This work investigates the relationship between pore pressure-dependent friction laws and the propagation of seismic ruptures, particularly the transition to supershear speeds. We present a numerical approach that couples fluid flow, rock deformation, and frictional contact, using stress-rate-dependent rate-and-state friction laws to simulate fault reactivation and rupture propagation. Our simulations demonstrate that the dependence of frictional properties on the effective normal stress rate can partially explain the occurrence of supershear ruptures, leading to a transition from sub-Rayleigh to supershear propagation patterns, as opposed to classical rate-and-state laws. We perform a parametric sweep, varying confining stresses, tectonic ratio, and fluid compressibility, and perform a dimensionless analysis to quantify the impact of hydromechanical parameters on supershear ruptures. Our analysis reveals that the stress drop during rupture is a key parameter in distinguishing between sub-Rayleigh and supershear rupture regimes. This study contributes to understanding the mechanisms that control fault friction behavior and its impact on seismic risk in underground reservoirs, which is crucial for the safe implementation of technologies such as green hydrogen storage and geothermal energy.
{"title":"Effects of pore pressure-dependent friction laws on supershear earthquakes","authors":"Sandro Andrés , David Santillán , Ruben Juanes , Luis Cueto-Felgueroso","doi":"10.1016/j.gete.2026.100787","DOIUrl":"10.1016/j.gete.2026.100787","url":null,"abstract":"<div><div>Supershear earthquakes are a particular class of seismic events in which the rupture velocity exceeds the shear wave velocity. These high-speed ruptures challenge conventional fault mechanics and have significant implications for the assessment of seismic hazards. This work investigates the relationship between pore pressure-dependent friction laws and the propagation of seismic ruptures, particularly the transition to supershear speeds. We present a numerical approach that couples fluid flow, rock deformation, and frictional contact, using stress-rate-dependent rate-and-state friction laws to simulate fault reactivation and rupture propagation. Our simulations demonstrate that the dependence of frictional properties on the effective normal stress rate can partially explain the occurrence of supershear ruptures, leading to a transition from sub-Rayleigh to supershear propagation patterns, as opposed to classical rate-and-state laws. We perform a parametric sweep, varying confining stresses, tectonic ratio, and fluid compressibility, and perform a dimensionless analysis to quantify the impact of hydromechanical parameters on supershear ruptures. Our analysis reveals that the stress drop during rupture is a key parameter in distinguishing between sub-Rayleigh and supershear rupture regimes. This study contributes to understanding the mechanisms that control fault friction behavior and its impact on seismic risk in underground reservoirs, which is crucial for the safe implementation of technologies such as green hydrogen storage and geothermal energy.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100787"},"PeriodicalIF":3.7,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-03DOI: 10.1016/j.gete.2026.100786
Mina Fattahi, Reza Imam
Compacted Impervious Liners (CILs) play a critical role in landfills by preventing environmental pollution. Where local soils do not meet stringent design criteria, soil amendment with bentonite is widely adopted to enhance properties of CILs. This study focuses on examining the behavior of a typical sand-bentonite mixture used as CIL and investigating the cracking patterns, self-healing properties in terms of hydraulic conductivity and uniaxial strength under wet-dry and freeze-thaw cycles, and effects of bentonite type and percentage on these properties. CT scanning and image processing results showed that in higher plasticity mixtures containing more sodium bentonite, cracks formed during wet-dry cycles tend to be larger and surficial; however, following freeze-thaw cycles, they are thinner, shorter and distributed uniformly over the sample depth. In the lower plasticity calcium bentonite mixtures, the cracking patterns during the two types of environmental stresses are reversed. Moreover, three patterns of changes in hydraulic conductivity and self healing during wet-dry cycles depending on the bentonite type of the mixture are also identified. Possible explanations for the cracking and self-healing observations are also provided. Effects of bentonite type and mixture plasticity on the various mixture properties including strength, stiffness, post-peak softening rate, failure mechanism, hydraulic conductivity, compaction properties, etc. are also examined. It was noticed that for the low PI mixture, wet-dry cycles finally lead to either increase or decrease in hydraulic conductivity depending on the mixture density.
{"title":"Cracking patterns, self-healing and properties of sand-bentonite liner under environmental stresses: A CT scanning and laboratory testing approach","authors":"Mina Fattahi, Reza Imam","doi":"10.1016/j.gete.2026.100786","DOIUrl":"10.1016/j.gete.2026.100786","url":null,"abstract":"<div><div>Compacted Impervious Liners (CILs) play a critical role in landfills by preventing environmental pollution. Where local soils do not meet stringent design criteria, soil amendment with bentonite is widely adopted to enhance properties of CILs. This study focuses on examining the behavior of a typical sand-bentonite mixture used as CIL and investigating the cracking patterns, self-healing properties in terms of hydraulic conductivity and uniaxial strength under wet-dry and freeze-thaw cycles, and effects of bentonite type and percentage on these properties. CT scanning and image processing results showed that in higher plasticity mixtures containing more sodium bentonite, cracks formed during wet-dry cycles tend to be larger and surficial; however, following freeze-thaw cycles, they are thinner, shorter and distributed uniformly over the sample depth. In the lower plasticity calcium bentonite mixtures, the cracking patterns during the two types of environmental stresses are reversed. Moreover, three patterns of changes in hydraulic conductivity and self healing during wet-dry cycles depending on the bentonite type of the mixture are also identified. Possible explanations for the cracking and self-healing observations are also provided. Effects of bentonite type and mixture plasticity on the various mixture properties including strength, stiffness, post-peak softening rate, failure mechanism, hydraulic conductivity, compaction properties, etc. are also examined. It was noticed that for the low PI mixture, wet-dry cycles finally lead to either increase or decrease in hydraulic conductivity depending on the mixture density.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100786"},"PeriodicalIF":3.7,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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